kernel/tools/iio/iio_utils.c

   1 /* IIO - useful set of util functionality
   2  *
   3  * Copyright (c) 2008 Jonathan Cameron
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published by
   7  * the Free Software Foundation.
   8  */
   9 #include <string.h>
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include <stdint.h>
  13 #include <dirent.h>
  14 #include <errno.h>
  15 #include <ctype.h>
  16 #include "iio_utils.h"
  17
  18 const char *iio_dir = "/sys/bus/iio/devices/";
  19
  20 static char * const iio_direction[] = {
  21         "in",
  22         "out",
  23 };
  24
  25 /**
  26  * iioutils_break_up_name() - extract generic name from full channel name
  27  * @full_name: the full channel name
  28  * @generic_name: the output generic channel name
  29  *
  30  * Returns 0 on success, or a negative error code if string extraction failed.
  31  **/
  32 int iioutils_break_up_name(const char *full_name, char **generic_name)
  33 {
  34         char *current;
  35         char *w, *r;
  36         char *working, *prefix = "";
  37         int i, ret;
  38
  39         for (i = 0; i < ARRAY_SIZE(iio_direction); i++)
  40                 if (!strncmp(full_name, iio_direction[i],
  41                              strlen(iio_direction[i]))) {
  42                         prefix = iio_direction[i];
  43                         break;
  44                 }
  45
  46         current = strdup(full_name + strlen(prefix) + 1);
  47         if (!current)
  48                 return -ENOMEM;
  49
  50         working = strtok(current, "_\0");
  51         if (!working) {
  52                 free(current);
  53                 return -EINVAL;
  54         }
  55
  56         w = working;
  57         r = working;
  58
  59         while (*r != '\0') {
  60                 if (!isdigit(*r)) {
  61                         *w = *r;
  62                         w++;
  63                 }
  64
  65                 r++;
  66         }
  67         *w = '\0';
  68         ret = asprintf(generic_name, "%s_%s", prefix, working);
  69         free(current);
  70
  71         return (ret == -1) ? -ENOMEM : 0;
  72 }
  73
  74 /**
  75  * iioutils_get_type() - find and process _type attribute data
  76  * @is_signed: output whether channel is signed
  77  * @bytes: output how many bytes the channel storage occupies
  78  * @bits_used: output number of valid bits of data
  79  * @shift: output amount of bits to shift right data before applying bit mask
  80  * @mask: output a bit mask for the raw data
  81  * @be: output if data in big endian
  82  * @device_dir: the IIO device directory
  83  * @name: the channel name
  84  * @generic_name: the channel type name
  85  *
  86  * Returns a value >= 0 on success, otherwise a negative error code.
  87  **/
  88 int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
  89                       unsigned *shift, uint64_t *mask, unsigned *be,
  90                       const char *device_dir, const char *name,
  91                       const char *generic_name)
  92 {
  93         FILE *sysfsfp;
  94         int ret;
  95         DIR *dp;
  96         char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
  97         char signchar, endianchar;
  98         unsigned padint;
  99         const struct dirent *ent;
 100
 101         ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
 102         if (ret < 0)
 103                 return -ENOMEM;
 104
 105         ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
 106         if (ret < 0) {
 107                 ret = -ENOMEM;
 108                 goto error_free_scan_el_dir;
 109         }
 110         ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
 111         if (ret < 0) {
 112                 ret = -ENOMEM;
 113                 goto error_free_builtname;
 114         }
 115
 116         dp = opendir(scan_el_dir);
 117         if (!dp) {
 118                 ret = -errno;
 119                 goto error_free_builtname_generic;
 120         }
 121
 122         ret = -ENOENT;
 123         while (ent = readdir(dp), ent)
 124                 /*
 125                  * Do we allow devices to override a generic name with
 126                  * a specific one?
 127                  */
 128                 if ((strcmp(builtname, ent->d_name) == 0) ||
 129                     (strcmp(builtname_generic, ent->d_name) == 0)) {
 130                         ret = asprintf(&filename,
 131                                        "%s/%s", scan_el_dir, ent->d_name);
 132                         if (ret < 0) {
 133                                 ret = -ENOMEM;
 134                                 goto error_closedir;
 135                         }
 136
 137                         sysfsfp = fopen(filename, "r");
 138                         if (!sysfsfp) {
 139                                 ret = -errno;
 140                                 fprintf(stderr, "failed to open %s\n",
 141                                         filename);
 142                                 goto error_free_filename;
 143                         }
 144
 145                         ret = fscanf(sysfsfp,
 146                                      "%ce:%c%u/%u>>%u",
 147                                      &endianchar,
 148                                      &signchar,
 149                                      bits_used,
 150                                      &padint, shift);
 151                         if (ret < 0) {
 152                                 ret = -errno;
 153                                 fprintf(stderr,
 154                                         "failed to pass scan type description\n");
 155                                 goto error_close_sysfsfp;
 156                         } else if (ret != 5) {
 157                                 ret = -EIO;
 158                                 fprintf(stderr,
 159                                         "scan type description didn't match\n");
 160                                 goto error_close_sysfsfp;
 161                         }
 162
 163                         *be = (endianchar == 'b');
 164                         *bytes = padint / 8;
 165                         if (*bits_used == 64)
 166                                 *mask = ~0;
 167                         else
 168                                 *mask = (1ULL << *bits_used) - 1;
 169
 170                         *is_signed = (signchar == 's');
 171                         if (fclose(sysfsfp)) {
 172                                 ret = -errno;
 173                                 fprintf(stderr, "Failed to close %s\n",
 174                                         filename);
 175                                 goto error_free_filename;
 176                         }
 177
 178                         sysfsfp = 0;
 179                         free(filename);
 180                         filename = 0;
 181                 }
 182
 183 error_close_sysfsfp:
 184         if (sysfsfp)
 185                 if (fclose(sysfsfp))
 186                         perror("iioutils_get_type(): Failed to close file");
 187
 188 error_free_filename:
 189         if (filename)
 190                 free(filename);
 191
 192 error_closedir:
 193         if (closedir(dp) == -1)
 194                 perror("iioutils_get_type(): Failed to close directory");
 195
 196 error_free_builtname_generic:
 197         free(builtname_generic);
 198 error_free_builtname:
 199         free(builtname);
 200 error_free_scan_el_dir:
 201         free(scan_el_dir);
 202
 203         return ret;
 204 }
 205
 206 /**
 207  * iioutils_get_param_float() - read a float value from a channel parameter
 208  * @output: output the float value
 209  * @param_name: the parameter name to read
 210  * @device_dir: the IIO device directory in sysfs
 211  * @name: the channel name
 212  * @generic_name: the channel type name
 213  *
 214  * Returns a value >= 0 on success, otherwise a negative error code.
 215  **/
 216 int iioutils_get_param_float(float *output, const char *param_name,
 217                              const char *device_dir, const char *name,
 218                              const char *generic_name)
 219 {
 220         FILE *sysfsfp;
 221         int ret;
 222         DIR *dp;
 223         char *builtname, *builtname_generic;
 224         char *filename = NULL;
 225         const struct dirent *ent;
 226
 227         ret = asprintf(&builtname, "%s_%s", name, param_name);
 228         if (ret < 0)
 229                 return -ENOMEM;
 230
 231         ret = asprintf(&builtname_generic,
 232                        "%s_%s", generic_name, param_name);
 233         if (ret < 0) {
 234                 ret = -ENOMEM;
 235                 goto error_free_builtname;
 236         }
 237
 238         dp = opendir(device_dir);
 239         if (!dp) {
 240                 ret = -errno;
 241                 goto error_free_builtname_generic;
 242         }
 243
 244         ret = -ENOENT;
 245         while (ent = readdir(dp), ent)
 246                 if ((strcmp(builtname, ent->d_name) == 0) ||
 247                     (strcmp(builtname_generic, ent->d_name) == 0)) {
 248                         ret = asprintf(&filename,
 249                                        "%s/%s", device_dir, ent->d_name);
 250                         if (ret < 0) {
 251                                 ret = -ENOMEM;
 252                                 goto error_closedir;
 253                         }
 254
 255                         sysfsfp = fopen(filename, "r");
 256                         if (!sysfsfp) {
 257                                 ret = -errno;
 258                                 goto error_free_filename;
 259                         }
 260
 261                         errno = 0;
 262                         if (fscanf(sysfsfp, "%f", output) != 1)
 263                                 ret = errno ? -errno : -ENODATA;
 264
 265                         break;
 266                 }
 267 error_free_filename:
 268         if (filename)
 269                 free(filename);
 270
 271 error_closedir:
 272         if (closedir(dp) == -1)
 273                 perror("iioutils_get_param_float(): Failed to close directory");
 274
 275 error_free_builtname_generic:
 276         free(builtname_generic);
 277 error_free_builtname:
 278         free(builtname);
 279
 280         return ret;
 281 }
 282
 283 /**
 284  * bsort_channel_array_by_index() - sort the array in index order
 285  * @ci_array: the iio_channel_info array to be sorted
 286  * @cnt: the amount of array elements
 287  **/
 288
 289 void bsort_channel_array_by_index(struct iio_channel_info *ci_array, int cnt)
 290 {
 291         struct iio_channel_info temp;
 292         int x, y;
 293
 294         for (x = 0; x < cnt; x++)
 295                 for (y = 0; y < (cnt - 1); y++)
 296                         if (ci_array[y].index > ci_array[y + 1].index) {
 297                                 temp = ci_array[y + 1];
 298                                 ci_array[y + 1] = ci_array[y];
 299                                 ci_array[y] = temp;
 300                         }
 301 }
 302
 303 /**
 304  * build_channel_array() - function to figure out what channels are present
 305  * @device_dir: the IIO device directory in sysfs
 306  * @ci_array: output the resulting array of iio_channel_info
 307  * @counter: output the amount of array elements
 308  *
 309  * Returns 0 on success, otherwise a negative error code.
 310  **/
 311 int build_channel_array(const char *device_dir,
 312                         struct iio_channel_info **ci_array, int *counter)
 313 {
 314         DIR *dp;
 315         FILE *sysfsfp;
 316         int count = 0, i;
 317         struct iio_channel_info *current;
 318         int ret;
 319         const struct dirent *ent;
 320         char *scan_el_dir;
 321         char *filename;
 322
 323         *counter = 0;
 324         ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
 325         if (ret < 0)
 326                 return -ENOMEM;
 327
 328         dp = opendir(scan_el_dir);
 329         if (!dp) {
 330                 ret = -errno;
 331                 goto error_free_name;
 332         }
 333
 334         while (ent = readdir(dp), ent)
 335                 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 336                            "_en") == 0) {
 337                         ret = asprintf(&filename,
 338                                        "%s/%s", scan_el_dir, ent->d_name);
 339                         if (ret < 0) {
 340                                 ret = -ENOMEM;
 341                                 goto error_close_dir;
 342                         }
 343
 344                         sysfsfp = fopen(filename, "r");
 345                         if (!sysfsfp) {
 346                                 ret = -errno;
 347                                 free(filename);
 348                                 goto error_close_dir;
 349                         }
 350
 351                         errno = 0;
 352                         if (fscanf(sysfsfp, "%i", &ret) != 1) {
 353                                 ret = errno ? -errno : -ENODATA;
 354                                 if (fclose(sysfsfp))
 355                                         perror("build_channel_array(): Failed to close file");
 356
 357                                 free(filename);
 358                                 goto error_close_dir;
 359                         }
 360                         if (ret == 1)
 361                                 (*counter)++;
 362
 363                         if (fclose(sysfsfp)) {
 364                                 ret = -errno;
 365                                 free(filename);
 366                                 goto error_close_dir;
 367                         }
 368
 369                         free(filename);
 370                 }
 371
 372         *ci_array = malloc(sizeof(**ci_array) * (*counter));
 373         if (!*ci_array) {
 374                 ret = -ENOMEM;
 375                 goto error_close_dir;
 376         }
 377
 378         seekdir(dp, 0);
 379         while (ent = readdir(dp), ent) {
 380                 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 381                            "_en") == 0) {
 382                         int current_enabled = 0;
 383
 384                         current = &(*ci_array)[count++];
 385                         ret = asprintf(&filename,
 386                                        "%s/%s", scan_el_dir, ent->d_name);
 387                         if (ret < 0) {
 388                                 ret = -ENOMEM;
 389                                 /* decrement count to avoid freeing name */
 390                                 count--;
 391                                 goto error_cleanup_array;
 392                         }
 393
 394                         sysfsfp = fopen(filename, "r");
 395                         if (!sysfsfp) {
 396                                 ret = -errno;
 397                                 free(filename);
 398                                 count--;
 399                                 goto error_cleanup_array;
 400                         }
 401
 402                         errno = 0;
 403                         if (fscanf(sysfsfp, "%i", &current_enabled) != 1) {
 404                                 ret = errno ? -errno : -ENODATA;
 405                                 free(filename);
 406                                 count--;
 407                                 goto error_cleanup_array;
 408                         }
 409
 410                         if (fclose(sysfsfp)) {
 411                                 ret = -errno;
 412                                 free(filename);
 413                                 count--;
 414                                 goto error_cleanup_array;
 415                         }
 416
 417                         if (!current_enabled) {
 418                                 free(filename);
 419                                 count--;
 420                                 continue;
 421                         }
 422
 423                         current->scale = 1.0;
 424                         current->offset = 0;
 425                         current->name = strndup(ent->d_name,
 426                                                 strlen(ent->d_name) -
 427                                                 strlen("_en"));
 428                         if (!current->name) {
 429                                 free(filename);
 430                                 ret = -ENOMEM;
 431                                 count--;
 432                                 goto error_cleanup_array;
 433                         }
 434
 435                         /* Get the generic and specific name elements */
 436                         ret = iioutils_break_up_name(current->name,
 437                                                      &current->generic_name);
 438                         if (ret) {
 439                                 free(filename);
 440                                 free(current->name);
 441                                 count--;
 442                                 goto error_cleanup_array;
 443                         }
 444
 445                         ret = asprintf(&filename,
 446                                        "%s/%s_index",
 447                                        scan_el_dir,
 448                                        current->name);
 449                         if (ret < 0) {
 450                                 free(filename);
 451                                 ret = -ENOMEM;
 452                                 goto error_cleanup_array;
 453                         }
 454
 455                         sysfsfp = fopen(filename, "r");
 456                         if (!sysfsfp) {
 457                                 ret = -errno;
 458                                 fprintf(stderr, "failed to open %s\n",
 459                                         filename);
 460                                 free(filename);
 461                                 goto error_cleanup_array;
 462                         }
 463
 464                         errno = 0;
 465                         if (fscanf(sysfsfp, "%u", &current->index) != 1) {
 466                                 ret = errno ? -errno : -ENODATA;
 467                                 if (fclose(sysfsfp))
 468                                         perror("build_channel_array(): Failed to close file");
 469
 470                                 free(filename);
 471                                 goto error_cleanup_array;
 472                         }
 473
 474                         if (fclose(sysfsfp)) {
 475                                 ret = -errno;
 476                                 free(filename);
 477                                 goto error_cleanup_array;
 478                         }
 479
 480                         free(filename);
 481                         /* Find the scale */
 482                         ret = iioutils_get_param_float(&current->scale,
 483                                                        "scale",
 484                                                        device_dir,
 485                                                        current->name,
 486                                                        current->generic_name);
 487                         if ((ret < 0) && (ret != -ENOENT))
 488                                 goto error_cleanup_array;
 489
 490                         ret = iioutils_get_param_float(&current->offset,
 491                                                        "offset",
 492                                                        device_dir,
 493                                                        current->name,
 494                                                        current->generic_name);
 495                         if ((ret < 0) && (ret != -ENOENT))
 496                                 goto error_cleanup_array;
 497
 498                         ret = iioutils_get_type(&current->is_signed,
 499                                                 &current->bytes,
 500                                                 &current->bits_used,
 501                                                 &current->shift,
 502                                                 &current->mask,
 503                                                 &current->be,
 504                                                 device_dir,
 505                                                 current->name,
 506                                                 current->generic_name);
 507                         if (ret < 0)
 508                                 goto error_cleanup_array;
 509                 }
 510         }
 511
 512         if (closedir(dp) == -1) {
 513                 ret = -errno;
 514                 goto error_cleanup_array;
 515         }
 516
 517         free(scan_el_dir);
 518         /* reorder so that the array is in index order */
 519         bsort_channel_array_by_index(*ci_array, *counter);
 520
 521         return 0;
 522
 523 error_cleanup_array:
 524         for (i = count - 1;  i >= 0; i--) {
 525                 free((*ci_array)[i].name);
 526                 free((*ci_array)[i].generic_name);
 527         }
 528         free(*ci_array);
 529         *ci_array = NULL;
 530         *counter = 0;
 531 error_close_dir:
 532         if (dp)
 533                 if (closedir(dp) == -1)
 534                         perror("build_channel_array(): Failed to close dir");
 535
 536 error_free_name:
 537         free(scan_el_dir);
 538
 539         return ret;
 540 }
 541
 542 static int calc_digits(int num)
 543 {
 544         int count = 0;
 545
 546         while (num != 0) {
 547                 num /= 10;
 548                 count++;
 549         }
 550
 551         return count;
 552 }
 553
 554 /**
 555  * find_type_by_name() - function to match top level types by name
 556  * @name: top level type instance name
 557  * @type: the type of top level instance being searched
 558  *
 559  * Returns the device number of a matched IIO device on success, otherwise a
 560  * negative error code.
 561  * Typical types this is used for are device and trigger.
 562  **/
 563 int find_type_by_name(const char *name, const char *type)
 564 {
 565         const struct dirent *ent;
 566         int number, numstrlen, ret;
 567
 568         FILE *namefp;
 569         DIR *dp;
 570         char thisname[IIO_MAX_NAME_LENGTH];
 571         char *filename;
 572
 573         dp = opendir(iio_dir);
 574         if (!dp) {
 575                 fprintf(stderr, "No industrialio devices available\n");
 576                 return -ENODEV;
 577         }
 578
 579         while (ent = readdir(dp), ent) {
 580                 if (strcmp(ent->d_name, ".") != 0 &&
 581                     strcmp(ent->d_name, "..") != 0 &&
 582                     strlen(ent->d_name) > strlen(type) &&
 583                     strncmp(ent->d_name, type, strlen(type)) == 0) {
 584                         errno = 0;
 585                         ret = sscanf(ent->d_name + strlen(type), "%d", &number);
 586                         if (ret < 0) {
 587                                 ret = -errno;
 588                                 fprintf(stderr,
 589                                         "failed to read element number\n");
 590                                 goto error_close_dir;
 591                         } else if (ret != 1) {
 592                                 ret = -EIO;
 593                                 fprintf(stderr,
 594                                         "failed to match element number\n");
 595                                 goto error_close_dir;
 596                         }
 597
 598                         numstrlen = calc_digits(number);
 599                         /* verify the next character is not a colon */
 600                         if (strncmp(ent->d_name + strlen(type) + numstrlen,
 601                             ":", 1) != 0) {
 602                                 filename = malloc(strlen(iio_dir) + strlen(type)
 603                                                   + numstrlen + 6);
 604                                 if (!filename) {
 605                                         ret = -ENOMEM;
 606                                         goto error_close_dir;
 607                                 }
 608
 609                                 ret = sprintf(filename, "%s%s%d/name", iio_dir,
 610                                               type, number);
 611                                 if (ret < 0) {
 612                                         free(filename);
 613                                         goto error_close_dir;
 614                                 }
 615
 616                                 namefp = fopen(filename, "r");
 617                                 if (!namefp) {
 618                                         free(filename);
 619                                         continue;
 620                                 }
 621
 622                                 free(filename);
 623                                 errno = 0;
 624                                 if (fscanf(namefp, "%s", thisname) != 1) {
 625                                         ret = errno ? -errno : -ENODATA;
 626                                         goto error_close_dir;
 627                                 }
 628
 629                                 if (fclose(namefp)) {
 630                                         ret = -errno;
 631                                         goto error_close_dir;
 632                                 }
 633
 634                                 if (strcmp(name, thisname) == 0) {
 635                                         if (closedir(dp) == -1)
 636                                                 return -errno;
 637
 638                                         return number;
 639                                 }
 640                         }
 641                 }
 642         }
 643         if (closedir(dp) == -1)
 644                 return -errno;
 645
 646         return -ENODEV;
 647
 648 error_close_dir:
 649         if (closedir(dp) == -1)
 650                 perror("find_type_by_name(): Failed to close directory");
 651
 652         return ret;
 653 }
 654
 655 static int _write_sysfs_int(const char *filename, const char *basedir, int val,
 656                             int verify)
 657 {
 658         int ret = 0;
 659         FILE *sysfsfp;
 660         int test;
 661         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 662
 663         if (!temp)
 664                 return -ENOMEM;
 665
 666         ret = sprintf(temp, "%s/%s", basedir, filename);
 667         if (ret < 0)
 668                 goto error_free;
 669
 670         sysfsfp = fopen(temp, "w");
 671         if (!sysfsfp) {
 672                 ret = -errno;
 673                 fprintf(stderr, "failed to open %s\n", temp);
 674                 goto error_free;
 675         }
 676
 677         ret = fprintf(sysfsfp, "%d", val);
 678         if (ret < 0) {
 679                 if (fclose(sysfsfp))
 680                         perror("_write_sysfs_int(): Failed to close dir");
 681
 682                 goto error_free;
 683         }
 684
 685         if (fclose(sysfsfp)) {
 686                 ret = -errno;
 687                 goto error_free;
 688         }
 689
 690         if (verify) {
 691                 sysfsfp = fopen(temp, "r");
 692                 if (!sysfsfp) {
 693                         ret = -errno;
 694                         fprintf(stderr, "failed to open %s\n", temp);
 695                         goto error_free;
 696                 }
 697
 698                 if (fscanf(sysfsfp, "%d", &test) != 1) {
 699                         ret = errno ? -errno : -ENODATA;
 700                         if (fclose(sysfsfp))
 701                                 perror("_write_sysfs_int(): Failed to close dir");
 702
 703                         goto error_free;
 704                 }
 705
 706                 if (fclose(sysfsfp)) {
 707                         ret = -errno;
 708                         goto error_free;
 709                 }
 710
 711                 if (test != val) {
 712                         fprintf(stderr,
 713                                 "Possible failure in int write %d to %s/%s\n",
 714                                 val, basedir, filename);
 715                         ret = -1;
 716                 }
 717         }
 718
 719 error_free:
 720         free(temp);
 721         return ret;
 722 }
 723
 724 /**
 725  * write_sysfs_int() - write an integer value to a sysfs file
 726  * @filename: name of the file to write to
 727  * @basedir: the sysfs directory in which the file is to be found
 728  * @val: integer value to write to file
 729  *
 730  * Returns a value >= 0 on success, otherwise a negative error code.
 731  **/
 732 int write_sysfs_int(const char *filename, const char *basedir, int val)
 733 {
 734         return _write_sysfs_int(filename, basedir, val, 0);
 735 }
 736
 737 /**
 738  * write_sysfs_int_and_verify() - write an integer value to a sysfs file
 739  *                                and verify
 740  * @filename: name of the file to write to
 741  * @basedir: the sysfs directory in which the file is to be found
 742  * @val: integer value to write to file
 743  *
 744  * Returns a value >= 0 on success, otherwise a negative error code.
 745  **/
 746 int write_sysfs_int_and_verify(const char *filename, const char *basedir,
 747                                int val)
 748 {
 749         return _write_sysfs_int(filename, basedir, val, 1);
 750 }
 751
 752 static int _write_sysfs_string(const char *filename, const char *basedir,
 753                                const char *val, int verify)
 754 {
 755         int ret = 0;
 756         FILE  *sysfsfp;
 757         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 758
 759         if (!temp) {
 760                 fprintf(stderr, "Memory allocation failed\n");
 761                 return -ENOMEM;
 762         }
 763
 764         ret = sprintf(temp, "%s/%s", basedir, filename);
 765         if (ret < 0)
 766                 goto error_free;
 767
 768         sysfsfp = fopen(temp, "w");
 769         if (!sysfsfp) {
 770                 ret = -errno;
 771                 fprintf(stderr, "Could not open %s\n", temp);
 772                 goto error_free;
 773         }
 774
 775         ret = fprintf(sysfsfp, "%s", val);
 776         if (ret < 0) {
 777                 if (fclose(sysfsfp))
 778                         perror("_write_sysfs_string(): Failed to close dir");
 779
 780                 goto error_free;
 781         }
 782
 783         if (fclose(sysfsfp)) {
 784                 ret = -errno;
 785                 goto error_free;
 786         }
 787
 788         if (verify) {
 789                 sysfsfp = fopen(temp, "r");
 790                 if (!sysfsfp) {
 791                         ret = -errno;
 792                         fprintf(stderr, "Could not open file to verify\n");
 793                         goto error_free;
 794                 }
 795
 796                 if (fscanf(sysfsfp, "%s", temp) != 1) {
 797                         ret = errno ? -errno : -ENODATA;
 798                         if (fclose(sysfsfp))
 799                                 perror("_write_sysfs_string(): Failed to close dir");
 800
 801                         goto error_free;
 802                 }
 803
 804                 if (fclose(sysfsfp)) {
 805                         ret = -errno;
 806                         goto error_free;
 807                 }
 808
 809                 if (strcmp(temp, val) != 0) {
 810                         fprintf(stderr,
 811                                 "Possible failure in string write of %s "
 812                                 "Should be %s written to %s/%s\n", temp, val,
 813                                 basedir, filename);
 814                         ret = -1;
 815                 }
 816         }
 817
 818 error_free:
 819         free(temp);
 820
 821         return ret;
 822 }
 823
 824 /**
 825  * write_sysfs_string_and_verify() - string write, readback and verify
 826  * @filename: name of file to write to
 827  * @basedir: the sysfs directory in which the file is to be found
 828  * @val: the string to write
 829  *
 830  * Returns a value >= 0 on success, otherwise a negative error code.
 831  **/
 832 int write_sysfs_string_and_verify(const char *filename, const char *basedir,
 833                                   const char *val)
 834 {
 835         return _write_sysfs_string(filename, basedir, val, 1);
 836 }
 837
 838 /**
 839  * write_sysfs_string() - write string to a sysfs file
 840  * @filename: name of file to write to
 841  * @basedir: the sysfs directory in which the file is to be found
 842  * @val: the string to write
 843  *
 844  * Returns a value >= 0 on success, otherwise a negative error code.
 845  **/
 846 int write_sysfs_string(const char *filename, const char *basedir,
 847                        const char *val)
 848 {
 849         return _write_sysfs_string(filename, basedir, val, 0);
 850 }
 851
 852 /**
 853  * read_sysfs_posint() - read an integer value from file
 854  * @filename: name of file to read from
 855  * @basedir: the sysfs directory in which the file is to be found
 856  *
 857  * Returns the read integer value >= 0 on success, otherwise a negative error
 858  * code.
 859  **/
 860 int read_sysfs_posint(const char *filename, const char *basedir)
 861 {
 862         int ret;
 863         FILE  *sysfsfp;
 864         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 865
 866         if (!temp) {
 867                 fprintf(stderr, "Memory allocation failed");
 868                 return -ENOMEM;
 869         }
 870
 871         ret = sprintf(temp, "%s/%s", basedir, filename);
 872         if (ret < 0)
 873                 goto error_free;
 874
 875         sysfsfp = fopen(temp, "r");
 876         if (!sysfsfp) {
 877                 ret = -errno;
 878                 goto error_free;
 879         }
 880
 881         errno = 0;
 882         if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
 883                 ret = errno ? -errno : -ENODATA;
 884                 if (fclose(sysfsfp))
 885                         perror("read_sysfs_posint(): Failed to close dir");
 886
 887                 goto error_free;
 888         }
 889
 890         if (fclose(sysfsfp))
 891                 ret = -errno;
 892
 893 error_free:
 894         free(temp);
 895
 896         return ret;
 897 }
 898
 899 /**
 900  * read_sysfs_float() - read a float value from file
 901  * @filename: name of file to read from
 902  * @basedir: the sysfs directory in which the file is to be found
 903  * @val: output the read float value
 904  *
 905  * Returns a value >= 0 on success, otherwise a negative error code.
 906  **/
 907 int read_sysfs_float(const char *filename, const char *basedir, float *val)
 908 {
 909         int ret = 0;
 910         FILE  *sysfsfp;
 911         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 912
 913         if (!temp) {
 914                 fprintf(stderr, "Memory allocation failed");
 915                 return -ENOMEM;
 916         }
 917
 918         ret = sprintf(temp, "%s/%s", basedir, filename);
 919         if (ret < 0)
 920                 goto error_free;
 921
 922         sysfsfp = fopen(temp, "r");
 923         if (!sysfsfp) {
 924                 ret = -errno;
 925                 goto error_free;
 926         }
 927
 928         errno = 0;
 929         if (fscanf(sysfsfp, "%f\n", val) != 1) {
 930                 ret = errno ? -errno : -ENODATA;
 931                 if (fclose(sysfsfp))
 932                         perror("read_sysfs_float(): Failed to close dir");
 933
 934                 goto error_free;
 935         }
 936
 937         if (fclose(sysfsfp))
 938                 ret = -errno;
 939
 940 error_free:
 941         free(temp);
 942
 943         return ret;
 944 }
 945
 946 /**
 947  * read_sysfs_string() - read a string from file
 948  * @filename: name of file to read from
 949  * @basedir: the sysfs directory in which the file is to be found
 950  * @str: output the read string
 951  *
 952  * Returns a value >= 0 on success, otherwise a negative error code.
 953  **/
 954 int read_sysfs_string(const char *filename, const char *basedir, char *str)
 955 {
 956         int ret = 0;
 957         FILE  *sysfsfp;
 958         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 959
 960         if (!temp) {
 961                 fprintf(stderr, "Memory allocation failed");
 962                 return -ENOMEM;
 963         }
 964
 965         ret = sprintf(temp, "%s/%s", basedir, filename);
 966         if (ret < 0)
 967                 goto error_free;
 968
 969         sysfsfp = fopen(temp, "r");
 970         if (!sysfsfp) {
 971                 ret = -errno;
 972                 goto error_free;
 973         }
 974
 975         errno = 0;
 976         if (fscanf(sysfsfp, "%s\n", str) != 1) {
 977                 ret = errno ? -errno : -ENODATA;
 978                 if (fclose(sysfsfp))
 979                         perror("read_sysfs_string(): Failed to close dir");
 980
 981                 goto error_free;
 982         }
 983
 984         if (fclose(sysfsfp))
 985                 ret = -errno;
 986
 987 error_free:
 988         free(temp);
 989
 990         return ret;
 991 }